KB aur MB ka farak — 10 KB kitna hota hai, 1 MB kitne KB ka
How much is 10 KB, why 1 MB and 1024 KB are the same rule, and why your phone shows a different file size than the upload page does. Plain arithmetic.
Updated
"How much is 10 KB" is asked thousands of times a month, and the honest answer needs two sentences rather than one number. A kilobyte is a unit of file weight, not of picture size, and the confusion between those two ideas is responsible for a large share of failed form uploads.
The units
A byte is one character of storage. A kilobyte is a thousand and twenty-four bytes, although operating systems increasingly round it to a thousand for display. A megabyte is a thousand and twenty-four kilobytes. So a portal writing maximum 1 MB and another writing maximum 1024 KB are stating exactly the same rule, and neither is stricter than the other.
That single fact resolves a surprising amount of anxiety. When one page in a set of instructions says 1 MB and another says 1000 KB, they are close enough that any file comfortably under a megabyte satisfies both, and there is nothing to reconcile.
What a kilobyte figure does not tell you
It tells you nothing about how wide the picture is. A 10 KB file can be a crisp 140 by 60 pixel signature, a soft 600 by 800 pixel photograph, or a blank white rectangle of any size at all. This is why searches like 10 kb signature size in pixels have no single answer: the two measurements are independent, and the same byte count buys different pixel counts depending on how much detail the image contains.
Three things decide the weight of a JPEG. Pixel count comes first — a twelve-megapixel phone photograph has roughly forty times the pixels of a 600 by 600 profile picture. Detail comes second: hair, grass, textured walls and sensor noise all cost bytes, while a plain studio backdrop costs almost nothing. Encoder quality comes last, and it is the only one a compression slider touches.
Why your phone and the portal disagree
Open the same file in your gallery, in a file manager, and in the portal's upload dialogue and you may see three slightly different numbers. There are two reasons. Some tools divide by a thousand and some by a thousand and twenty-four, which produces a two-and-a-half per cent difference. And some tools report the space the file occupies on disk, which is rounded up to a whole block, rather than the actual byte length that a validator measures.
The practical consequence: never aim exactly at the wall. If the ceiling is 50 KB, land at 46 or 47. If the floor is 10 KB, land at 11 or 12. That margin absorbs any rounding disagreement and costs you nothing visually.
Reading real rules
Indian portals state their limits in several styles, and it is worth learning to read them quickly.
A window with both walls: banking recruitment asks for a photograph between 20 KB and 50 KB and a signature between 10 KB and 20 KB, alongside pixel boxes for each (IBPS CRP Clerks-XIV notification).
A window with a wide range: the Civil Services upload sheet asks for a photograph of 20 to 300 KB and a signature of 20 to 100 KB, which is generous enough that quality is never the constraint (UPSC instructions for uploading documents).
A ceiling per document: the national scholarship portal's guidance caps each attached document at 200 KB and accepts PDF or JPEG (National Scholarship Portal FAQ).
A ceiling with a scanning hint, which is the most useful kind: a consular document upload page caps documents at 500 KB and notes that an A4 page scanned in colour at 100 dots per inch comes to roughly 200 to 250 KB (High Commission of India, Kampala — document upload). That sentence tells you the limit was written with real scans in mind, and it gives you a scanner setting instead of a guessing game.
Rough expectations, so you know when something is wrong
A tightly cropped signature on white paper: four to eight kilobytes at ordinary quality. A head-and-shoulders portrait at 200 by 230 pixels: fifteen to forty kilobytes. The same portrait at 600 by 600 pixels: sixty to a hundred and fifty. An A4 text page photographed in greyscale at two hundred dots per inch: eighty to two hundred kilobytes. An unedited photograph straight from a modern phone: two to six megabytes.
If your numbers are wildly outside these bands, look at the cause rather than compressing harder. A 400 KB signature usually means the scan includes half a desk. A 20 MB photograph usually means a high-resolution mode or a PNG export.
The MB rules that actually appear
Most Indian form rules live in kilobytes, but megabyte limits do exist, generally for proof documents rather than photographs. One state portal's upload page caps an identity proof at 1 MB and a signature at 500 KB, which is roomy by comparison with exam windows (Rajasthan Sanstha Aadhaar image upload). When you meet a megabyte limit, the usual mistake is over-compressing out of habit and submitting an unreadable scan for no reason.
The one-line summary
Kilobytes measure the file; pixels measure the picture; dots per inch connect pixels to centimetres. Fix the geometry first, then the weight, and leave yourself a small margin on each wall.